So I have to replace a ground strap on my wife's car, which is a bare, braided copper wire that's tinned and solder blocked in the ends.

old, broken grounding strap

Because this particular ground strap is on the bottom of the engine to the bottom of the frame, it's especially exposed to the elements. It's right by the front tire on an AWD car, so it's bound to get full of junk. The previous one did, and rusted in half. Cool, huh?

My question is twofold:

  1. Why do we use these bare, braided straps instead of a shielded wire? Is it the flexibility?
  2. Can I solder-block the ends and shrink-tube the replacement to protect it?

2 Answers 2


The main reason is flexibility as the environment the wire is in is subject to varying mechanical stresses and continuous vibration.

It's ok to rejoin the wire as a temporary measure but a repair and any shrink wrap will increase its rigidity and induce weak points elsewhere in the wire which will not last.

In my opinion as the wire has broken in two places already it's time to consider replacing it for a new one.

  • I'm not even suggesting putting the old one back on; it's being replaced without question. Now you've addressed my first question and touched on the second, but can you elaborate more on the second, under the assumption that I'm considering shrink-wrapping (or some other means of shielding) the brand new replacement? Dec 28, 2017 at 17:59
  • Ah ok.. Well even if you shrink wrap the new cable I very much doubt it will protect it for long. Even with shrink wrap moisture will still enter at the ends and perhaps even accelerate the rotting of the wire from the inside. At least in the open it can dry out.
    – Orb
    Dec 28, 2017 at 18:42

When you replace this with a new one, you can cover it - remember flexibility.

You can fit a longer one - if space allows and provide a loop for flexibility as well.

The manufacturer used the cheapest possible - so, as long as you make sure what is fitted meets the same specs such as resistance then improving it is fine.

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